A known prior-art process for transferring a layer, called the SMART CUT® process, comprises the following steps:                (a) providing a donor substrate and a support substrate made of materials having a first and second thermal expansion coefficient, respectively;        (b) forming an embrittlement region in the donor substrate so as to delimit a first part and a second part in the donor substrate on either side of the embrittlement region, the first part being intended to form the layer to be transferred to the support substrate;        (c) forming what is called a bonding layer between the first part of the donor substrate and the support substrate, the bonding layer having a preset thickness; and        (d) assembling the donor substrate to the support substrate.        
The donor substrate and the support substrate are conventionally subjected to a temperature increase in step (d). The donor substrate and the support substrate are also subjected to a temperature increase in subsequent steps consisting in:                fracturing the donor substrate in the embrittlement region using a heat treatment; and        strengthening the interfaces with an anneal.        
These temperature increases generate stresses in the structure comprising the donor substrate, the bonding layer and the support substrate via the differential thermal behavior caused by the donor substrate and the support substrate having different thermal expansion coefficients. These stresses can cause defects to appear in the structure (bulk defects and interface defects) and even to a substrate delaminating, depending on their magnitude.
The temperature increases are particularly large in the step of fracturing the donor substrate and in the annealing step for strengthening the interfaces, which steps are executed at temperatures of several hundred degrees Celsius, thus generating stresses of very high magnitudes in the structure. The step of fracturing the donor substrate and the annealing step for strengthening the interfaces are, therefore, steps that promote the appearance of defects in the structure and even delamination of a substrate.